As far as I know there is nothing unusual about a cockatial's mating process. They mate the same way as other birds. Also to my knowlege there are no fully terrestrial eggs fertilized externally. Perhaps some of the invertebates do?

Fertilization is definitely internal in birds via cloacal insemination and fertilization occurs even before the shell is processed around the egg...........thats what I studies way back about 5 yrs..........dont think things have changed much since then........

Wow...I thought I was the only one who used to believe birds fertilized eggs externally...My cockteil keeps laying them and they sit and sit, diligently...No little birds, ever...He won't touch her...He does hump his perch though...I wish he would get smart but this is like the 5th batch that I know he won't figure it out now...Any advice?